For example the outside temperature was 82 degrees, and I had the Thermostat set on 76 all night, and the interior temperature of the unit was at 80 degrees when I got home. No one was in or out as this was just setting outside of my house. It feels like cool air coming out of the ac but the unit is not comfortable.

Yes we are also pre-wired for second unit but I was hoping to make it though the rest of this year and install a second this winter.

The single unit AC should keep up with that kind of heat with no problem. I'm guessing the thermostat is not correct on the set temp. I've found mine to be off by a few degrees. I have a stand alone weather station that does indoor and outdoor temps and adjust the thermostat up/ down according to that. My old TT had the same thermostat and I did the same for that too. I do usually set the fan to auto. On the initial cool down I use the hi fan setting.

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I used to have a really nice motorhome
2016 Jeep Wrangler Unlimited

I don't own the unit that you have but one of the first mods I did was to install a digitalthermostat. It’s for the heater only since my a/c unit is either on or off. This keep the heat temp within 2 degrees and the mercury thermostat was sticking in the off position. Not good when the outside temps were in the 20’s. Not expensive and easy to install. Got it from Lowes.

We noticed when we picked ours up that the kitchen area has 3 additional outlets as well as the main A/C unit itself so we capped them off using some plastic lids trimmed to fit the grills. This worked and forced more air to each end of the trailer but noticed after using the A/C for a few minutes that condensation was forming on them so have since replaced them with some foil backed insulation to help insulate things to eliminate condensation.

Couple of things that I would recommend here before switching the thermostat out. The first thing to do is to switch the AC unit to the quick cool option by dumping the A/C into the main room where it is located vs. the vent system by opening the slide mechanism on the AC from the inside. If you can get a temp reading from the air coming out, check and see what the difference is between it and the outside air temp (you might just be able to check this by feel to see if it is cold or not).

This will give you an idea as to if your AC is working properly or not. If the AC coming out of the quick cool is cold, but the AC coming through the vent system is not, you might just have a leak throughout your vent system somewhere (probably caused by gaps where the holes were cut for the vents in the ceiling, where the vent system connects into the AC system, or both.) If you have leaks, the cold air is probably escaping into the roof itself rather than going into the camper and you will need to seal this up to fix the problem, or have a dealer do it.

I had a similar problem with my last camper and after going through the process in this thread, it was a night and day difference. I documented as much as possible here and it is really not that bad to check and correct if this is the problem.